In a network of communicating machines, such as for example an enterprise network or other computer network, the number of possible configurations, and the amount of data available regarding those possible configurations, grows rapidly with the size of that network. It sometimes occurs that users, such as network administrators or others, desire information about what configuration (or what subset of possible configurations) are currently true of the network.
For example and without limitation, a user might wish to know, of a network having 100,000 nodes, how many or what fraction of them are simultaneously using the “Windows 7™” operating system and the “Firefox™” browser, and of those, how many or what fraction of them are experiencing problems related to lack of free memory. Much other possible information about the network's configuration, whether seeking the presence or absence of a particular element, the prevalence of a particular element, or a correspondence between a 1st particular element and a 2nd particular element, might be of value, and might be requested by users from time to time.
However, the number of possible configurations, and the amount of data available regarding those possible configurations, grows rapidly with the size of the network. This can present numerous problems for known systems. For example and without limitation:                the desired amount of resources to find that information grows rapidly with the size of the network, making substantially all such requests for information relatively expensive in resources;        the desired amount of communication bandwidth available to report that data, and the desired amount of computing power available to analyze that data to determine whether the network is any particular user-selected set of possible configurations, again grows rapidly with the size of that network, again making substantially all such requests for information relatively expensive in resources;        the desired number of sources of that information, and the desired form of aggregation of that information, can make answers to such requests for information possibly erroneous, such as for example, in the event that any significant amount of the collected data is inaccurate;        the amount of latency in sending information through the network, whether limited by communication bandwidth, computing power, switching speeds, the speed of light, or otherwise, makes it difficult to assess in what state the network is at any particular moment. As to this latter point, known systems have difficulty even in determining a definitive moment at which the configuration of the network is scrutinized, which can make answers to such requests for information unhelpful, or possibly, meaningless.        
Known systems also have the drawback that they are unable to communicate or process that amount of information sufficiently quickly and with sufficiently little operational effect on the network. Known systems also have the drawback that they might involve significant hardware and software structures to be added to the network, just to provide their services; these hardware and software structures might themselves have problems with their creation, installation, operation, maintenance, and correction.